Published by Valve

Valve is an American-based video game publisher and developer.
History
Valve was found in 1996 by Gabe Newell and Mike Harrington. The company's first product to be released was a critically acclaimed shooter, Half-Life. After that, Valve launched its own digital distribution platform, Steam.
In 2015, Valve began developing hardware being interested in the Virtual Reality market.
Games
Valve is best known for their shooter IPs Half-Life, Team Fortress, and Portal, a MOBA game DoTA 2 and Source game engine.
Steam
Valve owns a digital distribution service Steam, which is the biggest service of this kind in the world. Steam customers can buy not only Valve games on Steam. In fact, any developer can publish their game on Steam and sell it there, paying a sales percentage to Valve. The customers can chat with other players and play online using the Steam Community service.